New York City Comptroller John Liu, center, escorts Serim Han, as she holds a picture of her husband Ki-Suck Han, and her daughter Ashley Han, 20, second from left, to a news conference Wednesday in New York.

NEW YORK — The police charged a homeless man Wednesday with murder by pushing a man on a subway platform in front of an oncoming train Monday.

The suspect, identified as Naeem Davis, had been taken into custody by the police Tuesday afternoon on 50th Street and Seventh Avenue, a block from an entrance to the subway platform where the police say he pushed Ki-Suck Han of Elmhurst, Queens, onto the tracks. Han was struck and killed by a Q train moments later.

Detectives questioned Davis, 30, for hours at the Midtown North precinct station, and Paul J. Browne, the department’s chief spokesman, said that during questioning Davis made statements implicating himself in the crime.

The murder charge was announced Wednesday after the police rounded up witnesses and conducted a lineup for witnesses to identify the attacker. The police initially said Davis was also charged with attempted murder but later said that was incorrect.

Cellphone video recorded by a subway rider on the 49th Street station platform showed what appeared to be a confrontation between Davis and Han. A freelance photographer working for The New York Post, who was also on the platform and took pictures of Han seconds before his death, said he had seen Han “flying through the air and onto the track.”

A law enforcement official said Davis had been arrested before for minor offenses including peddling. Vendors in the area where he was apprehended by the police on Tuesday said that they knew Davis and that he ran errands for them.

Davis does not have a fixed address, the police said.

The daytime crime prompted debate among many New Yorkers after a photo of Han — hanging onto the side of the train platform, unable to lift himself to safety — appeared on the cover of The New York Post on Tuesday. Witnessed by many on the platform, Han’s death raised questions about how bystanders in the city can — and perhaps, should — behave in moments of crisis.

The image, and others of Han in the tracks published by the paper, brought swift criticism of the photographer for shooting and not helping, and the newspaper for splashing the ghoulish image with the headline “Doomed.”

“Somebody’s taking that picture,” Al Roker said on NBC’s “Today” show on Tuesday. “Why aren’t they helping this guy up?”

The photographer, R. Umar Abbasi, who was on an unrelated assignment for The Post, has defended his actions, saying he was too far away to reach Han in time. He said his intention was not to photograph him but to use the camera’s flash to signal the train conductor to stop.

Abbasi said in an interview Tuesday that others on the platform did not step in to try to save Han. “Nobody helped,” he said. “People started running away.”